In the luxury motor home and recreational vehicle (RV) industry, there has been an increasing demand for motor homes or RV's having increased floor space and functions. In particular, luxury motor homes have seen the development of extendable or extendable rooms which enable the vehicle to comply with highway size restrictions when driving but which can be extended from the vehicle when parked in order to provide an increased amount of floor space to the occupants.
In the past, a variety of different mechanisms have been implemented in order to permit the extension and retraction of a extendable room including manual, hydraulic, mechanical screw systems and rack and gear systems.
With particular reference to rack and gear systems, various problems may exist, particularly in the extension and retraction of larger extendable rooms and the automation of that process. That is, in order to facilitate the extension and retraction of the extendable rooms, there has been a need for an efficient and effective drive mechanism which allows the room to be extended, supported, and retracted under automatic control.
In the past, examples of drive mechanisms for extendable rooms include those which are disclosed in various US patents including U.S. Pat. No. 5,577,351 which describes a extendable room which utilizes a camming linkage that allows an extendable room to be raised and lowered at its point of maximum extension to provide a floor which is flush with the main floor of the RV; U.S. Pat. No. 5,785,373 which describes a slide out room with a skid pad; U.S. Pat. No. 5,857,733 which describes a synchronization device for an extendable room utilizing a crossed rack and pinion system; U.S. Pat. No. 5,237,782 which describes an extendable room utilizing a worm gear mechanism and U.S. Pat. No. 5,333,420 which utilizes a single rack and gear drive mechanism.
None of these patents propose a system which addresses the problem of synchronized extension and retraction of both sides of a extendable room with a drive mechanism which ensures that the entire room can be extended and retracted uniformly.